According to Purdue University's website, the abbreviation for the word "assignment" is ASSG. This is listed as a standard abbreviation within the field of information technology.
According to the American Psychological Association (APA) format, the word to be abbreviated should be spelled in its entirety the first time it is used, and the abbreviation should be enclosed behind it in parentheses. When engaging in technical or academic writing, it is especially important to confirm that abbreviations are correct before using them in a document. Failure to do so may confuse the reader and cast doubt upon the credibility of the document. Purdue's website offers a comprehensive list of standard abbreviations.